The present invention relates to an agent for promoting the fattening of animals and to a method for promoting the fattening of animals. More precisely, the invention relates to an agent for promoting the fattening of animals, which contains, as an active ingredient, at least one of hexose-derived acids such as typically gluconic acid, and their non-toxic salts and intramolecular ester compounds, and to a method of promoting the fattening of animals by use thereof.
For promoting the growth of animals such as livestock, antibiotics such as tetracycline and avoparcin have heretofore been used by being added to feed as fattening promoters. However, these antibiotics often induce resistant bacteria through mutation in the body of animals. In addition, they may remain in the body of animals, and the human beings who have eaten the meat of the animals shall inevitably take the antibiotics. As a result, the potency of antibiotics serving as medicines will be thereby lowered.
Recently, therefore, substances except antibiotics have been investigated for fattening promoters for animals. For example, fumaric acid is used as a fattening promoter.
On the other hand, gluconic acid which is one typical example of hexose-derived acids has heretofore been widely used. For example, its intramolecular ester compound, glucono delta lactone is known as a coagulant for tofu (soybean curd); and calcium gluconate is known as a calcium supplement. In addition, sodium gluconate and potassium gluconate have been officially approved as food additives recently and are used in various edibles (International Patent No. WO94/09650).
The inventors of the present invention have tried administering gluconic acid and its derivatives, which are highly safe to living bodies, to animals and analyzing their activity to the living bodies. Having specifically examined their effect in the animal intestines, the inventors have found unexpectedly that they promote the growth of specific enterobacteria in the animals and that the thus-growing enterobacteria significantly increase the production of short-chain fatty acids which are effective for the growth of the living bodies. In addition, the inventors have further found that the production of substances that will be harmful to living bodies is reduced or eliminated.
That is, if hexose-derived acids and their non-toxic salts and intramolecular ester compounds (hereinafter the term xe2x80x9chexose-derived acidsxe2x80x9d generally includes all these compounds) are administered to animals, Megasphaera and Mitsuokella, precisely Mesgasphaera elsdenii and Mitsuokella multiacidus, among enterobacteria in the animals are specifically proliferated.
On the other hand, as compared with the absence of the hexose derived acids, the production of acetic acid, propionic acid and butyric acid which are short-chain fatty acids is promoted about 2 times, about 4 times and about 8 times more, respectively. At the same time, the production of lactic acid, succinic acid, ammonia and hydrogen sulfide which are reported to have some negative influences such as diarrhea, digestive tract ulcers, lumen acidosis, etc. on living bodies is reduced or eliminated.
Therefore, if the hexose-derived acids are given to animals, the production of short-chain fatty acids is promoted in the living bodies of the animals, and, as a result, the feed efficiency is improved remarkably and the fattening of the animals is thereby accelerated.